Maybe it's time to update General Competition Rule 7 from the old desert smoke bomb days and revise to include something like: Where the start area is located on an established motocross track, riders shall be allowed to pre-ride to the point where the course first leaves the motocross track. An off-course return path shall be utilized and all such pre-ridng shall cease 10 minutes prior to the scheduled start time.

Without such a rule, you inevitably have people who know the track and people who've never seen the track will be a hazard, not to mention disadvantaged. In the old days, this wasn't much of an issue, since you didn't often start on MX tracks. Today, this is a common occurrence.